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package javax.xml.bind.helpers;

import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.w3c.dom.Node;

import javax.xml.bind.JAXBException;
import javax.xml.bind.PropertyException;
import javax.xml.bind.UnmarshalException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.ValidationEventHandler;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.bind.attachment.AttachmentUnmarshaller;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamReader;
import javax.xml.transform.Source;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import java.io.File;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * Partial default <tt>Unmarshaller</tt> implementation.
 *
 * <p>
 * This class provides a partial default implementation for the
 * {@link javax.xml.bind.Unmarshaller}interface.
 *
 * <p>
 * A JAXB Provider has to implement five methods (getUnmarshallerHandler,
 * unmarshal(Node), unmarshal(XMLReader,InputSource),
 * unmarshal(XMLStreamReader), and unmarshal(XMLEventReader).
 *
 * @author <ul> <li>Kohsuke Kawaguchi, Sun Microsystems, Inc.</li> </ul>
 * @see javax.xml.bind.Unmarshaller
 * @since JAXB1.0
 */
public abstract class AbstractUnmarshallerImpl implements Unmarshaller {

  /**
   * handler that will be used to process errors and warnings during unmarshal
   */
  private ValidationEventHandler eventHandler =
      new DefaultValidationEventHandler();

  /**
   * whether or not the unmarshaller will validate
   */
  protected boolean validating = false;

  /**
   * XMLReader that will be used to parse a document.
   */
  private XMLReader reader = null;

  /**
   * Obtains a configured XMLReader.
   *
   * This method is used when the client-specified
   * {@link SAXSource} object doesn't have XMLReader.
   *
   * {@link Unmarshaller} is not re-entrant, so we will
   * only use one instance of XMLReader.
   */
  protected XMLReader getXMLReader() throws JAXBException {
    if (reader == null) {
      try {
        SAXParserFactory parserFactory;
        parserFactory = SAXParserFactory.newInstance();
        parserFactory.setNamespaceAware(true);
        // there is no point in asking a validation because
        // there is no guarantee that the document will come with
        // a proper schemaLocation.
        parserFactory.setValidating(false);
        reader = parserFactory.newSAXParser().getXMLReader();
      } catch (ParserConfigurationException e) {
        throw new JAXBException(e);
      } catch (SAXException e) {
        throw new JAXBException(e);
      }
    }
    return reader;
  }

  public Object unmarshal(Source source) throws JAXBException {
    if (source == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "source"));
    }

    if (source instanceof SAXSource) {
      return unmarshal((SAXSource) source);
    }
    if (source instanceof StreamSource) {
      return unmarshal(streamSourceToInputSource((StreamSource) source));
    }
    if (source instanceof DOMSource) {
      return unmarshal(((DOMSource) source).getNode());
    }

    // we don't handle other types of Source
    throw new IllegalArgumentException();
  }

  // use the client specified XMLReader contained in the SAXSource.
  private Object unmarshal(SAXSource source) throws JAXBException {

    XMLReader r = source.getXMLReader();
    if (r == null) {
      r = getXMLReader();
    }

    return unmarshal(r, source.getInputSource());
  }

  /**
   * Unmarshals an object by using the specified XMLReader and the InputSource.
   *
   * The callee should call the setErrorHandler method of the XMLReader
   * so that errors are passed to the client-specified ValidationEventHandler.
   */
  protected abstract Object unmarshal(XMLReader reader, InputSource source) throws JAXBException;

  public final Object unmarshal(InputSource source) throws JAXBException {
    if (source == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "source"));
    }

    return unmarshal(getXMLReader(), source);
  }


  private Object unmarshal(String url) throws JAXBException {
    return unmarshal(new InputSource(url));
  }

  public final Object unmarshal(URL url) throws JAXBException {
    if (url == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "url"));
    }

    return unmarshal(url.toExternalForm());
  }

  public final Object unmarshal(File f) throws JAXBException {
    if (f == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "file"));
    }

    try {
      // copied from JAXP
      String path = f.getAbsolutePath();
      if (File.separatorChar != '/') {
        path = path.replace(File.separatorChar, '/');
      }
      if (!path.startsWith("/")) {
        path = "/" + path;
      }
      if (!path.endsWith("/") && f.isDirectory()) {
        path = path + "/";
      }
      return unmarshal(new URL("file", "", path));
    } catch (MalformedURLException e) {
      throw new IllegalArgumentException(e.getMessage());
    }
  }

  public final Object unmarshal(java.io.InputStream is)
      throws JAXBException {

    if (is == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "is"));
    }

    InputSource isrc = new InputSource(is);
    return unmarshal(isrc);
  }

  public final Object unmarshal(Reader reader) throws JAXBException {
    if (reader == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "reader"));
    }

    InputSource isrc = new InputSource(reader);
    return unmarshal(isrc);
  }


  private static InputSource streamSourceToInputSource(StreamSource ss) {
    InputSource is = new InputSource();
    is.setSystemId(ss.getSystemId());
    is.setByteStream(ss.getInputStream());
    is.setCharacterStream(ss.getReader());

    return is;
  }


  /**
   * Indicates whether or not the Unmarshaller is configured to validate
   * during unmarshal operations.
   * <p>
   * <i><b>Note:</b> I named this method isValidating() to stay in-line
   * with JAXP, as opposed to naming it getValidating(). </i>
   *
   * @return true if the Unmarshaller is configured to validate during unmarshal operations, false
   * otherwise
   * @throws JAXBException if an error occurs while retrieving the validating flag
   */
  public boolean isValidating() throws JAXBException {
    return validating;
  }

  /**
   * Allow an application to register a validation event handler.
   * <p>
   * The validation event handler will be called by the JAXB Provider if any
   * validation errors are encountered during calls to any of the
   * <tt>unmarshal</tt> methods.  If the client application does not register
   * a validation event handler before invoking the unmarshal methods, then
   * all validation events will be silently ignored and may result in
   * unexpected behaviour.
   *
   * @param handler the validation event handler
   * @throws JAXBException if an error was encountered while setting the event handler
   */
  public void setEventHandler(ValidationEventHandler handler)
      throws JAXBException {

    if (handler == null) {
      eventHandler = new DefaultValidationEventHandler();
    } else {
      eventHandler = handler;
    }
  }

  /**
   * Specifies whether or not the Unmarshaller should validate during
   * unmarshal operations.  By default, the <tt>Unmarshaller</tt> does
   * not validate.
   * <p>
   * This method may only be invoked before or after calling one of the
   * unmarshal methods.
   *
   * @param validating true if the Unmarshaller should validate during unmarshal, false otherwise
   * @throws JAXBException if an error occurred while enabling or disabling validation at unmarshal
   * time
   */
  public void setValidating(boolean validating) throws JAXBException {
    this.validating = validating;
  }

  /**
   * Return the current event handler or the default event handler if one
   * hasn't been set.
   *
   * @return the current ValidationEventHandler or the default event handler if it hasn't been set
   * @throws JAXBException if an error was encountered while getting the current event handler
   */
  public ValidationEventHandler getEventHandler() throws JAXBException {
    return eventHandler;
  }


  /**
   * Creates an UnmarshalException from a SAXException.
   *
   * This is an utility method provided for the derived classes.
   *
   * <p>
   * When a provider-implemented ContentHandler wants to throw a
   * JAXBException, it needs to wrap the exception by a SAXException.
   * If the unmarshaller implementation blindly wrap SAXException
   * by JAXBException, such an exception will be a JAXBException
   * wrapped by a SAXException wrapped by another JAXBException.
   * This is silly.
   *
   * <p>
   * This method checks the nested exception of SAXException
   * and reduce those excessive wrapping.
   *
   * @return the resulting UnmarshalException
   */
  protected UnmarshalException createUnmarshalException(SAXException e) {
    // check the nested exception to see if it's an UnmarshalException
    Exception nested = e.getException();
    if (nested instanceof UnmarshalException) {
      return (UnmarshalException) nested;
    }

    if (nested instanceof RuntimeException)
    // typically this is an unexpected exception,
    // just throw it rather than wrap it, so that the full stack
    // trace can be displayed.
    {
      throw (RuntimeException) nested;
    }

    // otherwise simply wrap it
    if (nested != null) {
      return new UnmarshalException(nested);
    } else {
      return new UnmarshalException(e);
    }
  }

  /**
   * Default implementation of the setProperty method always
   * throws PropertyException since there are no required
   * properties. If a provider needs to handle additional
   * properties, it should override this method in a derived class.
   */
  public void setProperty(String name, Object value)
      throws PropertyException {

    if (name == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "name"));
    }

    throw new PropertyException(name, value);
  }

  /**
   * Default implementation of the getProperty method always
   * throws PropertyException since there are no required
   * properties. If a provider needs to handle additional
   * properties, it should override this method in a derived class.
   */
  public Object getProperty(String name)
      throws PropertyException {

    if (name == null) {
      throw new IllegalArgumentException(
          Messages.format(Messages.MUST_NOT_BE_NULL, "name"));
    }

    throw new PropertyException(name);
  }

  public Object unmarshal(XMLEventReader reader) throws JAXBException {

    throw new UnsupportedOperationException();
  }

  public Object unmarshal(XMLStreamReader reader) throws JAXBException {

    throw new UnsupportedOperationException();
  }

  public <T> JAXBElement<T> unmarshal(Node node, Class<T> expectedType) throws JAXBException {
    throw new UnsupportedOperationException();
  }

  public <T> JAXBElement<T> unmarshal(Source source, Class<T> expectedType) throws JAXBException {
    throw new UnsupportedOperationException();
  }

  public <T> JAXBElement<T> unmarshal(XMLStreamReader reader, Class<T> expectedType)
      throws JAXBException {
    throw new UnsupportedOperationException();
  }

  public <T> JAXBElement<T> unmarshal(XMLEventReader reader, Class<T> expectedType)
      throws JAXBException {
    throw new UnsupportedOperationException();
  }

  public void setSchema(Schema schema) {
    throw new UnsupportedOperationException();
  }

  public Schema getSchema() {
    throw new UnsupportedOperationException();
  }

  public void setAdapter(XmlAdapter adapter) {
    if (adapter == null) {
      throw new IllegalArgumentException();
    }
    setAdapter((Class) adapter.getClass(), adapter);
  }

  public <A extends XmlAdapter> void setAdapter(Class<A> type, A adapter) {
    throw new UnsupportedOperationException();
  }

  public <A extends XmlAdapter> A getAdapter(Class<A> type) {
    throw new UnsupportedOperationException();
  }

  public void setAttachmentUnmarshaller(AttachmentUnmarshaller au) {
    throw new UnsupportedOperationException();
  }

  public AttachmentUnmarshaller getAttachmentUnmarshaller() {
    throw new UnsupportedOperationException();
  }

  public void setListener(Listener listener) {
    throw new UnsupportedOperationException();
  }

  public Listener getListener() {
    throw new UnsupportedOperationException();
  }
}
